If there’s pus from an infected wound, abscess, or surgical site, this test provides the most reliable way to identify the cause. Your doctor will collect a small sample of the pus using a sterile swab or syringe. In the lab, the sample is cultured to see which aerobic bacteria (those that require oxygen) are present. Often, this is followed by an antibiotic sensitivity test to determine the most effective treatment. This test is essential because it moves beyond guesswork, giving your doctor precise information to prescribe the correct antibiotic, helping you recover faster and reducing the risk of complications.